Electric connectors that prevent water from entering a housing of the electrical connector at water pressures under a specified level are commonly used in vehicles. These waterproof connectors have a seal member formed of an elastomer arranged at a wire receiving opening of the housing where electric wires are connected to a contact or a fitting component of a mating connector. The seal member seals the entrance for the electric wires, which are connected to contacts inside the housing to prevent the influx of water therein. The seal member may either be an individual seal member where the seal member is individually attached to each of a plurality of the electric wires or a collective seal member where the seal member is attached to the plurality of the electric wires as a group.
FIGS. 5(a)-5(b) show an example of a waterproof connector with individual seal members, as described in Japanese Patent Application Kokai H7-142117. As shown in FIG. 5(a), an electric wire 20, which has a contact 10 connected to a distal end thereof, is inserted through a wire receiving through-hole of a cylindrically shaped seal member 30. A crimp barrel 12 of the contact 10 is crimped onto a core of the electric wire 20, and an insulation support 13 of the contact 10 is pressed onto an insulation covering of the electric wire 20 and onto a distal end of the seal member 30. The electric wire 20 is held within a contact housing cavity 41 of the housing 40, as shown in FIG. 5(b). Flanges 34, which are formed around an outside circumference of the seal member 30, press against an inside wall of an opening to the housing 40 to the seal the housing 40.
In the seal member 30 of FIGS. 5(a)-5(b), each of the contact housing cavities 41 are individually sealed and thereby excellent waterproof performance is ensured. However, since it is necessary to attach and seal each of the electric wires 20 separately, it requires a large amount of time to assemble this type of waterproof connector.
FIGS. 6(a)-6(b) show an example of a waterproof connector with a collective seal member, as described in Japanese Patent Application Kokai 2001-15204. As shown in FIGS. 6(a)-6(b), a seal member 50 made from an elastomer is formed to have a plurality of wire receiving through-holes 52. An electric wire 20 connected to a contact 10 housed in a contact housing cavity 11 of a connector housing 70 is inserted through each of the wire receiving through-holes 52. A seal member cover 60 is positioned on the connector housing 70.
In the seal member 50 of FIGS. 6(a)-6(b), it is difficult to simultaneously insert the electric wires 20 into the wire receiving through-holes 52 of the seal member 50 during assembly of the waterproof connector. Therefore, each of the electric wires 20 is inserted successively. In order for an adequately tight seal to be formed between the seal member 50 and the electric wires 20, an inside diameter of the wire receiving through-holes 52 is made to be slightly smaller than an outside diameter of the electric wires 20. The seal member 50 therefore compresses around a circumference of the wire receiving through-holes 52 where the electric wire 20 has been inserted, which causes the adjacent wire receiving through-holes 52 to deform. Accordingly, as the number of inserted electric wires 20 increases, the more difficult the electric wire insertion process becomes. Additionally, the compression rate of the seal member 50 diminishes which compromises the seal member's sealing properties.
As shown in FIG. 6(b), in order to address this problem, a circumferential groove 53 is formed in the seal member 50 around the circumference of each of the electric wire receiving through-holes 52 and a cylindrically projecting partition wall 63 is formed around the circumference of each of the wire receiving through-holes 52 in the seal member cover 60. When the seal member cover 60 is assembled to the seal member 50, the partition walls 63 fit into the corresponding grooves 53. As a result, the wire receiving through-holes 52 are individually isolated, and it is possible to minimize the effects of the deformation of the seal member 50 on adjacent wire receiving through-holes 52.
FIGS. 7(a)-7(b) show an example of a waterproof connector with a collective seal member, as described in Japanese Patent Application Kokai H11-354195. As shown in FIG. 7(a), seal member 80 is divided into zones 81 that are disposed vertically and horizontally across the seal member 80. Each of the zones 81 in the illustrated embodiment has three wire receiving through-holes 82 for a total holding capacity of 27 electric wires. Each of the zones 81 is divided by a lattice shaped groove 83. This groove 83 receives a seal member cover 90 having substantially elliptical-shaped lattice apertures 91 formed to retain the zones 81, as shown in FIG. 7(b). With this structure, even when employing large seal members through which a large number of the electric wires pass, the seal member 80 can be viewed as having smaller, independent seal members, which allow the insertion of the electric wires without causing inadequate sealing due to diminished compression rate. The structure of the seal member 80, however, prevents the waterproof connector in which it is contained from being adequately miniaturized.